On Sunday night, dozens of gunmen with suspected ties to notorious Islamist terror group Boko Haram murdered more than 40 university students as they slept in dormitories at an agricultural college in Yobe, northeastern Nigeria. This is just the latest carnage to grip the county since an executive-order from President Goodluck Jonathan kicked off an offensive in May, aiming to root out the shadowy rebels. Here’s a quick rundown of who they are and what they stand for.

1. The group was founded by a firebrand cleric called Mohammed Yusuf

Boko Haram is a Sunni terrorist organization that claims links to Al Qaeda and other groups of a similar ideological bent, both in the region and internationally. The group’s current incarnation was founded in 2003 under the leadership of a young Islamic cleric named Mohammed Yusuf. He was killed during a failed uprising against the Abuja government in July 2009 that spread across four northern states, but was successfully crushed by security forces. During the crackdown, Yusuf was arrested and killed while in custody. Since his death, his former deputy Abubakar Shekau has taken Boko Haram’s reins of power and launched a violent campaign largely targeting police stations, federal institutions and Christian villages across northeast Nigeria.

2. They kill students because they hate Western civilization

A rough translation of Boko Haram is: “Western civilization is forbidden.” The group’s main goal is to establish an Islamic caliphate within the country, which would allow for the implementation of sharia law. Boko Haram sees public schools as places where students are brainwashed by a “Western” curriculum, and earmarks them as significant targets in its war to drive secular, federal institutions from Nigeria’s Islamic heartland.

3. The head of the leader of Boko Haram is worth $2 million more than the head of the leader of the Afghan Taliban

To date, Boko Haram is believed to have been responsible for more than 3,500 deaths in Nigeria. Government troops have reported success against the rebels during a summer offensive. However, such claims are difficult to independently verify. Boko Haram does not posses the numbers or firepower needed to overthrow the state, but the fear is that they will consolidate ties with other insurgents in Africa, including the Algerian Al­ Qaeda and Somalia’s Al-Shabab, responsible for the recent massacre at Nairobi’s Westgate Mall. The U.S. government’s bounty for Boko Haram leader Abubakar Shekau stands at $7 million. To put this in perspective, it’s $2 million more than what’s offered for the Afghan Taliban’s top man, Mullah Omar.

4. They don’t have many supporters, not even in Nigeria’s Muslim heartland

Boko Haram’s stronghold has traditionally resided in the Nigeria’s northeastern hinterlands. These are home to most of the country’s Muslim communities, but many are part of the Sufi sect and do not share Boko Haram’s extremist ideology. That doesn’t give them much protection from Nigerian troops, however, who have launched multiple offensives against Boko Haram over the years. Rights groups have accused state security forces of razing civilians’ homes during these campaigns, and torturing and summarily executing people with suspected, albeit largely unproven, ties to Boko Haram.